A comparison of protein concentrations and energy in breast milk from preterm and term mothers.

The concentrations of milk specific and plasma proteins were compared in milk from mothers of preterm and term infants. Energy content was also determined. Immunoglobulin A was significantly increased in preterm milk, but there was no difference in the concentration of any other proteins or in the energy content. Both protein and energy varied to a greater extent in samples of preterm milk. We propose a hypothesis to explain the higher concentration of total nitrogen reported in preterm milk.